Hi pafurijaz, I think the issue is that the filleter in the geometry library that MoI uses is not able to build a fillet with this type of edge topology:



The problem is that a fillet segment needs to be constructed between these 2 faces, but they do not share an edge in common, they only share a vertex in common:



This will probably be a limitation in MoI's filleting until I'm able to get a different geometry library set up for handling filleting.

- Michael